The LOFAR View of Cosmic Magnetism

Abstract

The origin of magnetic fields in the Universe is an open problem in astrophysics and fundamental physics. Polarization observations with the forthcoming large radio telescopes will open a new era in the observation of magnetic fields and should help to understand their origin. At low frequencies, LOFAR (10-240 MHz) will allow us to map the structure of weak magnetic fields in the outer regions and halos of galaxies, in galaxy clusters and in the Milky Way via their synchrotron emission. Even weaker magnetic fields can be measured at low frequencies with help of Faraday rotation measures. A detailed view of the magnetic fields in the local Milky Way will be derived by Faraday rotation measures from pulsars. First promising images with LOFAR have been obtained for the Crab pulsar-wind nebula, the spiral galaxy M51, the radio galaxy M87 and the galaxy clusters A2255 and A2256. With help of the polarimetric technique of "Rotation Measure Synthesis", diffuse polarized emission has been detected from a magnetic bubble in the local Milky Way. Polarized emission and rotation measures were measured for more than 20 pulsars so far.

Summary of a review talk given at the Annual Meeting of the Astronomische Gesellschaft "The Bright and the Dark Sides of the Universe", Hamburg, 2012 September 24-28

References in corpus (14)

• Turbulence and Magnetic Fields in the Large Scale Structure of the Universe
• Strong magnetic fields in normal galaxies at high redshifts
• A low-frequency radio halo associated with a cluster of galaxies
• Magnetism in the spiral galaxy NGC 6946: magnetic arms, depolarization rings, dynamo modes and helical fields
• A Global Probe of Cosmic Magnetic Fields to High Redshifts
• Evolution of magnetic fields in galaxies and future observational tests with the Square Kilometre Array
• The "toothbrush-relic": evidence for a coherent linear 2-Mpc scale shock wave in a massive merging galaxy cluster?
• Global galactic dynamo driven by cosmic-rays and exploding magnetized stars
• M87 at metre wavelengths: the LOFAR picture
• The supernova-regulated ISM. II. The mean magnetic field
• First LOFAR observations at very low frequencies of cluster-scale non-thermal emission: the case of Abell 2256
• Magnetic field structures of galaxies derived from analysis of Faraday rotation measures, and perspectives for the SKA
• Magnetic field amplification by shocks in galaxy clusters: application to radio relics
• Rotation measure synthesis at the 2 m wavelength of the FAN region: Unveiling screens and bubbles

Cited by in corpus (16)

• The LOFAR Two-metre Sky Survey - I. Survey Description and Preliminary Data Release
• Magnetic Fields in Spiral Galaxies
• The LOFAR Multifrequency Snapshot Sky Survey (MSSS) I. Survey description and first results
• The nature of the low-frequency emission of M51: First observations of a nearby galaxy with LOFAR
• Spectrum and Anisotropy of Turbulence from Multi-Frequency Measurement of Synchrotron Polarization
• Magnetic fields in the nearby spiral galaxy IC 342: A multi-frequency radio polarization study
• Plasma turbulence in the interstellar medium
• The far-infrared - radio correlation in dwarf galaxies
• BeyondPlanck I. Global Bayesian analysis of the Planck Low Frequency Instrument data
• Constraints on the spectral index of polarized synchrotron emission from WMAP and Faraday-corrected S-PASS data
• Do magnetic fields influence gas rotation in galaxies?
• Spectropolarimetry with the Giant Metrewave Radio Telescope at 610 MHz: a case study of two Southern Compact Group fields
• Wide-band Rotation Measure Synthesis
• Broadband Polarized Radio Emission Detected from Starlink Satellites Below 100 MHz with NenuFAR
• Polarised radiative transfer, rotation measure fluctuations and large-scale magnetic fields
• Gravitational Waves sourced by Gauge Fields during Inflation